package string;

public class StringBuilderDemo {
    public static void main(String[] args) {

        StringBuilder builder1=new StringBuilder("a");
        for (int i=0;i<100000;i++){
            builder1.append(i);
        }
        System.out.println("执行完毕");


        String str="好好学习Java";
        StringBuilder builder=new StringBuilder(str);

        //append():追加内容---在末尾追加
        builder.append(",为了找个好工作");
        System.out.println(builder);//好好学习Java,为了找个好工作

        //replace():替换部分内容(含头去尾)
        builder.replace(9,16,"就是为了赚钱");
        System.out.println(builder);//好好学习Java,就是为了改变世界

        //delete():删除部分内容(含头去尾)
        builder.delete(0,8);//删除下标为0到7的
        System.out.println(builder);//

        //insert():插入内容
        builder.insert(0,"活着");
        System.out.println(builder);//活着,就是为了改变世界






        /*StringBuilder builder1=new StringBuilder();//空字符串
        StringBuilder builder2=new StringBuilder("abc");//abc串

        //String和StringBuilder互相转换:
        String str="abc";
        StringBuilder builder3=new StringBuilder(str);//abc串
        String str2=builder3.toString();*/
    }
}
